Petermann calves again

Petermann Glacier has calved another large ice island, about half the size
of the calving of two years ago, which amounts to about two Manhattans.

This is what it looks like:

This second big calving (spotted this time by Arcticicelost80) is another spectacular event on Greenland this year, following retreats of the Jakobshavn Glacier and lowest reflectivity of the Greenland ice sheet on record (see blog post), leading to unprecedented flooding in the southwest of Greenland. This calving was expected to happen, as the rift in the glacier has been there for years (see this thorough explanation by glacier expert Mauri Pelto).

From the Icy Seas blog:

This morning Petermann Glacier lost another ice island of a size comparable to what it lost in 2010:

The break-off point has been visible for at least 8 years in MODIS imagery propagating at speeds of 1 km/year towards Nares Strait. The fracture also extended further across the floating ice sheet from the northern towards its southern side.

This event is still evolving, Trudy Wohleben of the Canadian Ice Service noticed it first (as in 2010) after reviewing MODIS imagery. Several people in several countries are monitoring and assessing the situation, but a first estimate of its size is 200 km^2 (3 Manhattans), I will revise this figure as soon as I got my hands on the raw data.

Read more here.

Two years ago Patrick Lockerby was the first to tell the world about the big calving that occurred at Petermann Glacier. The Arctic Sea Ice blog followed suit shortly afterwards. The whole event garnered a lot of attention, popularizing the island of Manhattan as an area measurement tool (square metre, square kilometre, Manhattan ;-) ). This second big calving in as many years doesn't come as a surprise, as attested by this article on the New York Times blog from August last year:

Thanks to satellites and other instruments, researchers do know what is happening to ocean and air temperatures in northwest Greenland. They have been warming briskly of late, as global-warming theory predicted decades ago that they would for the whole Arctic.

Dr. Box finds a drastic increase in sea-surface temperatures in the region, and a sharp decline in sea ice. Scientists suspect that warmer water is circulating under Greenland’s floating ice shelves and causing them to weaken. But given the dearth of measurements from beneath Petermann, they do not have hard proof that is what happened in this case.

The breakup of the Petermann ice shelf fits into a broader picture. Many lines of evidence suggest that melting and breakup of Greenland ice, a phenomenon once concentrated on the southern end of that island, has spread to the colder northwest corner. As I reported last year, many scientists are worried about the overall fate of the Greenland ice sheet, especially the prospect that its melting could raise global sea levels substantially.

(...)

Dr. Box said another chunk of the Petermann Glacier, this one about twice the size of Manhattan, is now on the verge of breaking loose.

Dr. Box was right. Some more info on the blog of the Byrd Polar Research Center blog last year:

In response to the question: How abnormal is this event? Jason notes: "The August 2010 ice calving at Petermann is the largest in the observational record for Greenland" Falkner et al. (2011) scoured the observations and found no evidence of an event this large in scattered observations since 1876. Johannessen et al. (2011) identified the next largest observed Petermann calving event ocurring in 1991, being 58% as large as the 2010 event.

Another image can be added to these two posted in the same BPRC blog post (check out the little Eiffel towers on the left that give an idea about this mamma's magnitude):

When it comes to those "dearth of measurements" mentioned in the article, Andreas Münchow, a sea-going physical oceanographer from the University of Delaware, is supposed to go to Nares Strait (here to be precise) on the Canadian Coast Guard Ship Henry Larsen at the beginning of August to retrieve instruments that have recorded ocean current, temperature, salinity, and ice thickness data at better than hourly intervals from 2009 through 2012. As Dr. Münchow says in a comment following the blog post I alluded to at the top:

I am crunching numbers … this is a very worrisome event that will make our lives to get a ship recover our instrumentation more challenging and risky. I hope that this ice island will stay inside the fjord until we have safely entered and exited Nares Strait the first 2-3 weeks in August.

Interestingly enough the remnants from the previous calving still linger, and are closely followed by Environment Canada:

Here's a video of one of those chunks, back in June 2011:

 

And another video as seen from an airplane in August 2011:

 

Comments

[Account Deleted]

I guess we'll never know exactly the time of calving. Radar images after the failure Envisat'a not. Earthquakes of a magnitude more 2.5 have not been reported.

[Espen Olsen]

Hi Arcticicelost.

Just spoke to Greenland Tv / Radio, I am sure they will bring the story, at least it is a local story!

[Espen Olsen]

I estimate it to be about half the size of the 2010 calving!

[Account Deleted]

The most amazing thing that the breakaway occurred in mid-July. The last was in late summer - the end of August.

So maybe this is not the most interesting of the ice shelf calving this summer. :)

[Neven]

Arcticicelost80 and Espen, thanks for being so sharp! I'm still adding to the blog post, so refresh.

[Espen Olsen]

I told the reporter from Greenland Radio / Tv that it must be a massive experience to see and especially hear when that piece breaks of, imagine the sound down that fjord, better than any rock concerts!!!

[Espen Olsen]

It will be broadcasted today in Greenland with references to "our" site, u are welcome Neven and to Arcticicelost, I was just about to link to those Modis when I saw your report, but as long as it is in the "family" I am ok!

[Espen Olsen]

Neven: We need an alert message system, can you think a solution? I believe our "organisation" are far more alert than any in this field, think of how many "eyes" we all got!

[Account Deleted]

Another old article on topic

http://glacierchange.wordpress.com/2010/03/27/petermann-glacier/

[dorlomin]

Visually spectacular.

[Ian Allen]

So it WAS a crack I saw on the arctic.io image from the 14th. Have been fooled before by well placed clouds so I didn't dare say.
Do we know if the fjord leads right to the middle of Greenland or not? this image is a bit vague, looks like it could do.
http://upload.wikimedia.org/wikipedia/commons/8/8b/Topographic_map_of_Greenland_bedrock.jpg

[Espen Olsen]

I just did some research on the calving time.

It must have happened later than this:

Aqua/MODIS
2012/198
07/16/2012
10:25 UTC

Because it is not not on that image!
http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2012198102500-2012198103000.500m.jpg

[Neven]

Post is more or less finished now...

[Espen Olsen]

Good work Neven!

[Account Deleted]

http://glacierchange.wordpress.com/2010/03/27/petermann-glacier/
"The glacier velocity is close to 1 km per year."

So for 2 years (2010-2012) the glacier moved over a 2 km. Now the glacier broke off about 10 km in depth.

Does anyone know where the boundary of the glacier during the 30s warming in Greenland?

[crandles]

>"Do we know if the fjord leads right to the middle of Greenland or not?"

Yep, the ground stays below sealevel all the way into central greenland basin. Similarly for ilulissat glacier

[me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk-]

I just did some research on the calving time.

It must have happened later than this:

Aqua/MODIS
2012/198
07/16/2012
10:25 UTC

Espen, Patrick L said it occurred on Aug 4th, 2010.

Phil.

[cynicus]

"Yep, the ground stays below sealevel all the way into central greenland basin. Similarly for ilulissat glacier"
Holy cr*p!

Someone better send in the autonomous robot submarine that was used on Antarctic PIG glacier to survey how far the ocean is intruding below the glacier...

Yes, it's always 'someone' else, but I hereby volunteer to join the survey! I can do the dishes and vacuum the quarters to make myself useful. :p

[Werther]

Well...what do you say. That's something while you're in counting meltponds near Ilulissat! All together this is one dire season for Greenland!

[Greg Wellman]

"Yep, the ground stays below sealevel all the way into central greenland basin. Similarly for ilulissat glacier"

That topo map from wikipedia disagrees. It's very close, and the map isn't a very high resolution, but it's the highest rez map of Greenland's bedrock elevation I've seen. So, is there a well-substantiated source for sea level channels to the central basin?

[James Benison]

How ironic.

I came to this site to report the calving, but obviously others beat me to it.

My understanding is that Petermann is so little studied that nobody even knows where the sill is, let alone the details of the glacier bedrock.

[crandles]

>"So, is there a well-substantiated source for sea level channels to the central basin?"

I have seen such a map in a lecture video online. Hope I can find it again, in the meantime, this has been linked here before:

http://membrane.com/sidd/greenrockturn.html

[Ethan O'Connor]

Greg - The wikipedia greenland bedrock topography map linked above is based on the ETOPO1 global relief data set (http://www.ngdc.noaa.gov/mgg/global/etopo1sources.html).

ETOPO1 bases its Greenland bedrock topography on the NSIDC 5KM Greenland Bedrock grid, hosted at http://nsidc.org/data/nsidc-0092.html and based on Bamber et al 2001.

The Bamber paper is worth a read, but suffice to say neither the processed grid nor the sampling frequency over the ice really have the resolution to address questions of continuous below-sea-level paths to the interior. (http://www.cpom.org/research/jlb-ag.pdf)

CReSIS at KU hosts the raw data sets the 5KM grid was produced with and a lot of data from subsequent field seasons: https://data.cresis.ku.edu/#RDS but they state, "We do not currently have plans to update the Greenland grid."

So, there is room for some data crunching here :)

As for well-substantiated sea level channels, I don't know :)

[Account Deleted]

Greg Wellman, I think the exact answer is no. Until now, map specified.

http://www.nasa.gov/mission_pages/icebridge/news/spr12/index.html
"IceBridge got a running start on May 7 with a newly designed Northeast Grid mission, one of six flights meant to examine bedrock topography in northeast Greenland."

[James Benison]

Even if a below sea level bedrock channel into the interior does not exist, that does not mean all is fine and dandy.

A slew of publications just came out in recent days describing ice sheet "saddle collapse" as a mechanism that could explain rapid sea level rise.

My personal opinion is that everything we are currently witnessing is already totally obsolete. When the sea ice goes arctic conditions are going to change very radically. Predictions need to be made with that in mind. Current thinking tries to extrapolate what the greenland ice cap will do with an ice covered arctic sea. Any realistic person knows that the arctic sea ice is now temporary.

[Ethan O'Connor]

James -- Indeed.

http://www.nature.com/nature/journal/v487/n7406/fig_tab/nature11257_F3.html

may be the money shot re saddle collapse. 18 meter / year thickness loss across 1000s of square kilometers of ice sheet... 1.5km of ice thickness lost in 200 years.

[Artful Dodger]

In 2010, the calving event occurred on the Spring tide. When the grounded ice island hung up at the fjord entrance, it also remained there until the following Spring tide.

So, does anyone know when the last Spring tide occurred at Petermann fjord?

[Rob Dekker]

Pfff, Greenland is getting hammered pretty bad this year. First the albedo changes, then the record floods, and now the Petermann.

By the way, to the west of the Petermann, there is a huge ice field (some 4x the width of Petermann) that seems to extent right up to the water of Nares strait. Is that a glacier as well ? Or is there a wide mountain or clif or so there that prevents the ice from flowing into Nares strait ?

[Andreas Muenchow]

We are about 4 days short of spring tide in adjacent Nares Strait which is forcing the tide in Petermann Fjord as determined by the model of Padman and Erofeeva (2004) which agrees very well with (sealevel and velocity) observations in Nares Strait. A problem in tidal (and other modeling) is that we do not know something as basic as the bottom depth inside the fjord. We had hoped to improve on this for the area where the ice shelf disappeared in 2010, but the new calving may very well prevent such work as no sane sailor will be caught to the north of the new ice island. As it moves towards Nares Strait, we will only be able to survey seaward of the ice island. If it moves into Nares Strait, we will only be able to work to the south of the ice island. So, I hope it stays where it is, but that is unlikely.

[David Einstein]

@Rob I believer that the large glacier you refer to is the Humboldt Glacier http://glacierchange.wordpress.com/2010/09/04/humboldt-glacier-retreat-greenland/

[James Benison]

The Humboldt Glacier has been a scary looking thing for a long time. But it rests above sea level and does not move very quickly.

The thing I keep trying to emphasize is that past and current behavior of the Greenland Ice is quite meaningless. When the Arctic Sea Ice is gone that place is going to be a completely different world.

[Rob Dekker]

Thanks David, for that link to Humboldt.
The thing looks very scary indeed (because it is so wide and large). There is 5000 Gton ice sitting on that bed. But looking at the cross section of the bed gives me some confidence that it will remain slow moving for a while. That is...until surface melting will thin it enough so that it starts floating as well....

[Daniel Bailey]

FWIW, I had a really nice (IMEO) comment all spec'd out, but Typepad kept eating it. I have made an appeal for divine intervention from the lord of this blog for august aid for this unworthy person.

[Artful Dodger]

Hey, Yooper! Here's a little tip for dealing with Typepad: before you click 'Post', copy your comment into your clipboard. Then reload the page. Your comment should be preserved *at least with Firefox*. Paste in the comment if neccesary, then 'Post' it.

Looking forward to your Educated comment ;^)

[Artful Dodger]

Andreas, thanks for the info on Petermann tides. Be safe out there!

I've been meaning to ask this question of the group for some time: If you had $8 Million to spend on Arctic Research, how who you spend it?

Let me start off the discussion with the suggestion that I would deploy some autonomous sea gliders into the Arctic to gather temp/salinity profiles, and post them to a big public site. I would set up virtual picket lines on all the major gateways to the Arctic, and start modeling heat flows...

[Neven]

And here is the divine intervention from the lord of this blog for august aid for Daniel 'The Yooper' Bailey, posting his comment for him (too many links and images perhaps?).

---

IMHO, a few points to consider:

1. The glacier field to the SW of Peterman is indeed Humboldt. It is in little danger of enhanced flows of ice like at Jakobshavn, but may experience occasional bursts of calving (enhanced Zwally effect).

2. Petermann grounding line. Per Rignot and Steffen 2008, the grounding line is not far from the recent calving event:

Furthermore, Rignot and Steffen 2008 discovered the existence of melt channels underneath the floating portion of the tongue leading right up to the grounding line of the floating portion of the glacier. Additionally, they were able to detect seawater intrusions into those channels:

Closeup of ice-stream velocities of NW Greenland glaciers

Changes in those velocities

3. The ice stream with the biggest potential to increase its flows, due to both bedding and its penetration deep into the GIS itself, is not Petermann but Zachariae, in NE Greenland:

4. In regards to the "Saddle collapse" paper by Gregoire et al 2012, the topography of the Laurentide Ice Sheet is significantly different from that of the GIS. The LIS had several ice domes with saddles in-between, such as exist today in Antarctica (not advocating something similar will occur in Antarctica, just noting a similarity). The GIS, on the other hand, is more of a titanic ridge in its structure (Source). Other differences of significance are insolation and seasonal length differences. And latitude. So not a fair comparator.

5. As noted by the various graphics located in the source listed for my comment number 4 above, Greenland is geomorphologically bowl-shaped: a coastal ringing belt of mountains interspersed with vents to the sea, with its core below sea level. Once mass-losses due to calving of its outlet glaciers ramps up, Zachariae will take the lead in export losses, with Petermann also playing a significant role. Jakobshavn, with its narrow throat squeezed by mountains, will be a player as well, but its maximal calving output will be dwarfed by the two behemoths of the north.

My two cents, anyway.

[Rob Dekker]

Thanks, Neven, for this addition to your post.
I am especially shocked by the melt rate of the Petermann tongue. 20 meter melt per year implies that some 200 W/m^2 is available, right up to the grounding line of the glacier. Where would all that heat come from ?

[Neven]

Rob, that comment was written by SkS contributor Daniel Bailey. I just posted it for him because TypePad didn't let him.

[Daniel Bailey]

@ Rob Dekker

That would be from the ocean itself. This is at least partly addressed in Rignot & Steffen 2008 (which I referenced above). Basal thinning of the floating tongue by oceanic intrusions is a known factor. Now factor in a warming Arctic Ocean from a warming North Atlantic intrusion...

This is at least one of the factors contributing to the low profile that Petermann has at the calving edge.

Research area from Münchow et al 2011 linked above

[Daniel Bailey]

@ Artful Dodger

Appreciate the tip, but that isn't the issue. I compose comments offline in Notepad, preview in the comments box editor at SkS and then preview here at Neven's. For the apparently intermittent issue noted above, I have no explanation.

Sometimes Typepad refuses to give me the ReCaptcha password challenge & pretends to post the comment directly complete with unique URL. Which then disappears upon refresh or loading that unique URL in a different browser window. Like my posting issues last nite. This morning, password challenge was issued. Go figure.

[idunno]

I see the world's media has gone into a feeding frenzy over this story...

http://www.google.co.uk/webhp?sourceid=chrome-instant&ie=UTF-8#hl=en&gs_nf=1&ds=n&pq=greenland%20glacier&cp=19&gs_id=1t&xhr=t&q=greenland+petermann&pf=p&tbs=qdr:d&tbm=nws&sclient=psy-ab&oq=greenland+petermann&gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=c9d2f4dd80392ad4&biw=1002&bih=671

NOT. I wonder what Justin Bieber thinks about it...

http://www.google.co.uk/search?hl=en&gl=uk&tbm=nws&q=justin+bieber&oq=justin+bieber&gs_l=news-cc.12..43j0l9j43i400.703.4133.0.7006.13.8.0.5.5.0.354.1427.3j2j1j2.8.0...0.0.1XZLyMvBFHs#q=justin+bieber&hl=en&gl=uk&tbm=nws&source=lnt&tbs=qdr:d&sa=X&ei=wWEFUNmKHKqg0QXF4ZzNBw&ved=0CCUQpwUoAg&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=c9d2f4dd80392ad4&biw=1002&bih=671

[Espen Olsen]

This is 2nd time this von Münchhausen takes the honer, perhaps that is what we call scientific integrity!

[Artful Dodger]

Yes Yooper, TP has behaved that way for me as well, at least as long as since Neven upgraded to the Pro version... good job you save in Notepad ;^)

Now back to the $8 Million Question:

[Daniel Bailey]

"Now back to the $8 Million Question"

Umm, you mean, "Why is it pink?"

[Jeffrey Davis]

We were in Alaska earlier this summer and the routine calving off glaciers in Glacier Bay would receive lots of oohs and ahhhs from everyone with us. The size of the largest icebergs were some small multiple of yards across. 40 or 50 yards maybe. The usual ones were a couple of feet across. I could imagine a witness to the current huge calving wouldn't even know what he was seeing for a long time. Without the muted thunder of the crack would there be any local tangible phenomenon at all?

[Espen Olsen]

This report from Greenlandic Broadcasting Corporation about the calving of Petermann yesterday:

http://knr.gl/da/nyheder/gigantisk-isbjerg-br%C3%A6kket-af

[crandles]

>"the $8 Million Question"

I am sure lots of good science would come from that.

By the time the money is available, then spent on such gliders, then built, deployed, collected, data analysed, written up into publication, peer reviewed, published, modellers get the information and work out how to use the information beneficially in their models, run those models ....

will the arctic already be seasonally ice free?

Is there a sufficient risk of seasonally ice free conditions developing and this having noticable effects on climate through altering typical path of jet stream? Is this severe enough that we should be prioritising researching regional climate severe weather impacts from changes in snow and ice cover?

It is quite possible that climate models are just not up to this task and research in this direction would be doomed to not be very useful. I would want to talk to Myles Allen. Maybe it would be pointless, but I would want to consider adapting/extending climateprediction.net / weather @ home to run lots of models with lots of different snow and ice cover forcings with a view to trying to gather information on changes of frequency of different extreme events in different regions.

I would suggest that only CPDN type modeling facility could do the number of runs of climate models necessary in a fairly short period of time.

Cost - 3 or 4 post docs for a year or two should come in around or under £400k - less than 10% of the $8M. Can you manage on a few less glyders?

[Aaron Lewis]

Glaciers slide or flow DOWN mountain valleys and are supported by their beds as they move from a cooler environment into a warmer environment. Petermann and Jakobshavn Isbrae are over fjords that are well below sea level If they they suppored by their beds, then they flow UPWARDs to their terminus. Thus, Petermann and Jakobshavn Isbrae are deep horizontal flows driven by pressures in the ice massive. They have different ice dynamics than glaciers.

The fact that these ice flows are associated with deep fjords suggests that they have the power to go anywhere that they want - even through kilometers of bedrock.

[Espen Olsen]

But how can you then explain the word Bre, which is a Norwegian word for glaciers, and from where the English word originates, no matter whether they are on land or sea.

[Steve Bloom]

Or, Neven, you could think of the perimeter of the central sheet (i.e. the comparatively low-altitude bits immediately adjacent to the barrier mountains) as one big annular saddle. The outlet ends of the major drainage basins could be thought of the same way. IOW I'm not at all convinced that the saddle melt process lacks application to the GIS.

[idunno]

Hi all,

Dr Muenchow has an excellent follow-up piece:

http://icyseas.org/2012/07/17/petermann-glacier-and-2010-and-2012-ice-islands/

(and the media, bless them, are starting to cover this. at the time I posted the links above, there were 2 news stories on this, and about 35,000 on justin bieber)

[Realglacier]

What did Bieber do, I missed it. This is certainly an event I expected this summer, but not this early. There is not a next rift like there was in 2010, indicating the next likely calving point. It is certainly hard to keep up with the changes on an ice sheet that is notably slow to change.

[Artful Dodger]

Yooper: "Why is it pink?" -- of course, to ease the task of recovery... and I suspect to repel all those barnacles. ;^)

Chris: excellent idea to crowd source some of the science. I recall how successful the SETI@home movement was... but i also suspect that 4 more PhD's announcing that the Arctic is melting won't change anything.

My interest in the sea gliders is more to explore the salinity gradients AFTER the first sea ice free Summer. If the Arctic ocean somehow remains stratified, then there is a chance for a short-term recover.

If storms churn up the surface layer and mix it with the deeper warm layers, well it's game over. That's the next big defensive line for the "armies of de Nile."

[crandles]

>"4 more PhD's announcing that the Arctic is melting won't change anything."

True, but it was aimed more at preparation for weird weather if that is possible.

>"to explore the salinity gradients AFTER the first sea ice free Summer. If the Arctic ocean somehow remains stratified"

So why picket the entries rather than a few well spaced in the Arctic?

[Espen Olsen]

North East Greenland:
We have another "half" calving just off the 79th Fjord Glacier and the Zachariae Ice Bre next door, the ice in this area is a combination of both sea ice and glacier ice. The whole piece of ice about 15.000 - 20.000 km2 looks like it will disintegrate soon, and on the Modis images of today the northern part of this piece has broken of about 120 km2 and more cracks are clearly seen in the rest of the ice.

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2012200065500-2012200070000.250m.jpg

[Artful Dodger]

Chris wrote: "So why picket the entries rather than a few well spaced in the Arctic?"

Agreed. The 'gateway pickets' task is well suited to fixed tethered buoys, like the ones deployed in the Bering Strait. Unfortunately that data isn't publicly available, at least not on demand and in near real-time.

Not sure how many sea gliders fit into a $8M bill these days, but one nice feature is their mobility, as compared to the fixed or iced-tethered buoys of today. You can send command to a sea glider to explore a particular area of interest.

Again, I'd like to see more salinity/temp vertical profiles over a wide area. I think that's what will become the defining change in the nature of the Arctic Ocean during the transition to perennially sea ice free conditions.

[Bob Wallace]

"Why is it pink?"

Could be that the lead engineer thought it was a lovely shade of grey....

[crandles]

Where did the $8M figure come from?

[Account Deleted]

idunno, is first thousand. Indifference is not.

http://www.google.ru/#q=petermann+glacier&hl=ru&newwindow=1&tbm=nws&prmd=imvns&source=lnt&tbs=qdr:w&sa=X&ei=-_AGUKiKB_H04QSTnN30CA&ved=0CCMQpwUoAw&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=f1809a1b37c1d741&biw=800&bih=431

[Artful Dodger]

"Where did the $8M figure come from?"

Years ago, I read an interview with U2 frontman and celebrity environmentalist Bono. The Reporter asked "if you had $8 Million, what would you do?" Bono replied, "I'd start a Newspaper".

I don't know where the reporter got the figure $8M, but I presume it had something todo with U2's earnings.

[Kevin McKinney]

The "Spring Tides" question got lost in the thread, but FWIW:

Unlike most tidal phenomena, which tend to be localized, Spring Tides (and their converse, Neap Tides) are global. Spring Tides coincide with the famous (to Scrabble players) "syzygy" which features Sun, Earth and Moon in alignment. At this time, Lunar and Solar gravitational tugs reinforce one another. Neaps occur when the three bodies form a right angle.

Which means that Spring Tides occur at New Moon and Full Moon, Neaps at First Quarter and Third Quarter. Today is the New Moon:

http://www.calendar-365.com/moon/moon-phases.html

[Warzypants]

Nice to see the news has at last hit the mainstream, with it being the number 1 read item on www.bbc.com just at the moment.

[Twemoran]

Some nasty cookie situation has kept me from posting for days - It's so good to be back.

Warzypants
Great to see someone is paying attention!

Kevin
Spring tides in the Arctic at least lag the syzygy by a day or two. Morris Jessup is due early morning of the 21st

http://www.tide-forecast.com/locations/Cape-Morris-Jesup-North-Greenland/tides/latest

I wouldn't have expected Petermann to calve without a boost from the tide, or at least waiting until the fast ice had gone. Amazing what high temperatures can accomplish.
Can't help wonder if there was an under ice pulse of melt water, similar to the flooding of the Walker River.

Terry

[Espen Olsen]

The Chinese Icebreaker and research vessel "Xue Long" just entered Chukchi Sea on its way to the pole:

http://www.marinetraffic.com/ais/default.aspx?mmsi=412863000&centerx=-168.176&centery=69.40643&zoom=10&type_color=9

[Twemoran]

CBC (Canada) did a nice piece on the calving event in the evening news.

Terry

[idunno]

Dr Muenchow has an interesting piece on the oceanography of the Petermann fjord:

http://icyseas.org/2012/07/20/oceanography-of-petermann-fjord/

[Account Deleted]

"Below I show this first and subsequent mapping of Petermann Glacier (Falkner et al., 2011):"

Important evidence that the current retreat of Petermann glacier unique over the past 140 years observations. Ocean warming.

[Espen Olsen]

North East Greenland, Joekelbugt, two large pieces of the ice pack has broken off, it is hard to see because of the clouds covering the area:

http://rapidfire.sci.gsfc.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl2_143.A2012203041000-2012203041500.250m.jpg

[logicman]

Greetings to all.
I have been 8unable to write for some time due to a painful arm problem - improving now.

Well done on this story, Neven! I missed this one due to not using computer so I got the news here.

A quick check of MODIS rapidfire shows a well-developed calving at 18:25 UTC on 14th July.
http://lance-modis.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl1_143.A2012196182500-2012196183000.250m.jpg

Some images from prior to that one show cloud hovering over the crack. Considering the heat and vapor that is released when ice cracks, I would consider those clouds to be a tell-tale of crack propagation.

Expect more smaller chunks to calve this year.

Sorry, that's all for now - I need to limit my typing so as not to strain my arm again. Hope to resume blogging soon.

[Artful Dodger]

Patrick, welcome back old boy! You are greatly missed. Your hypothesis in 2010 has come true with the Petermann calving of 2012. Good job. Hope you'll drop in for a minute or two frequently now!

Cheers,
Lodger

[Espen Olsen]

Patrick, nice to you back on the "ice" again!

Regards Espen

[idunno]

Patrick, so pleased to see you're back.

The strange band in the Petermann turned out to be a wedge of multiyear ice, which is now splitting in two at the entrance to the Nares Strait.

[Twemoran]

Patrick, You have been missed.

Wonder if any of the voice recognition software might help.

Terry

[Espen Olsen]

North east Greenland, Joekelbugt:
As reported this morning, 3 very large pieces of ice broke of the fast ice pack in the last 24 hours, the total area estimate is believed to be a total of about 4500 km2 or the same as the average size of Great Salt Lake (US) or more than 6 times the size of Singapore, so we are talking bulky stuff.

[Espen Olsen]

Petermann Glacier:

Patrick, I believe too, we will see another calving soon, especially on the left side (looking downhill) were the there is a "corner" of ice and a small glacier (ice outlet) entering from Washington land, the pressure from this outlet could possibly break of the Petermann ice.

[Espen Olsen]

Petermann Fjord:

I realized there is one more island in the mouth of the fjord on the right side, opposite the side where Joe Island(named after the famous Joe Ebierbing an inuit pathfinder) is located, do any of you guys know what is the name of this island?
More info:Hans Island named after Hans Hendrick another famous inuit pathfinder.

[Andreas Muenchow]

The July-14, 2012 Terra image at 23:15, e.g., http://lance-modis.eosdis.nasa.gov/cgi-bin/imagery/single.cgi?image=crefl1_143.A2012196231500-2012196232000.250m.jpg does show the crack that has been advancing for at least 8 years, but it does not show the crack of the image earlier that day showing clouds or cloud shadows. Sea smoke forms when there is a large temperature difference between the surface ocean at freezng (-1.7 deg.-C) and the air as is common during the winter, but rare in the summer.

I think the island opposite to Joe Island at the entrance to Petermann Fjord is called Offrey Island on NOAA charts, but the spelling may be wrong, especially from a Danish perspective. A bottom pressure sensor to measure tides we deployed there in 2003 was lost and presumably destroyed by ice, as we could not recover it in either 2006 or 2007. We are planing to move an automated weather station from the Canadian Cape Baird to Joe Island in 2-3 weeks from now ... if the ice island stays inside the fjord and/or we can savely get to Joe Island via helicopter from the ship. Exciting stuff either way ...

[Espen Olsen]

Andreas,

Thanks for the info regarding Offrey Island.

[Andreas Muenchow]

Most welcome, but the name of the island appears to be "Offley" [British Parlimentary Papers from 1877, that I, hopefully legally, posted at http://muenchow.cms.udel.edu/html/Coppinger1876.pdf] This is also the first report that I am aware of that mentions and maps Petermann Fjord and Glacier.

Fun reading and considering how far we all have come in a mere 150 years ... Perhaps, if we'd do our explorations the way it was done then, we'd have more ice now as global warming and climate change would not be a factor impacting ice as it sure does now ...

[Espen Olsen]

Andreas,

Are you sure it is called Offley Island or is it off Offley Island, since what I can see Offley is opposite Washington Land? Or am I wrong, its about twice the size of Joe Island?

[Andreas Muenchow]

Espen:

The first paragraph of the original report settles it:

http://muenchow.cms.udel.edu/html/Coppinger1876.pdf

The link above does not work because a stupid "]" got in the way. Notice the very precise description as "On leaving Cape Tyson and Offley Island, which were considered to mark the north-east side of the mouth of the [Petermann] fjord ..."

These are the people who described places and geographies that had not been seen or visited by anyone not an Inuit. Amazing how clear they wrote ... no photography either, they had to paint and sketch ... no GPS, they had to use sextants and the stars to get latitude and keep time very accurately to get longitude. None of these are trivial matters while camping with poor equipment in the wilderness believing that there perhaps was open water at the North Pole.

[Espen Olsen]

Andreas,

Amazing stuff, now I understand they didn't need Modis, internet and whatever, the description tells it all (nearly), but what triggers me most is, they were in for a Real Rock Concert up there, anyone who ever heard ice cracking must understand what it sounds like up in those tunnels (fjords) and with that amount of ice (at that time) it must have been a f...... great show!

[Werther]

http://www.youtube.com/watch?v=HB3K5HY5RnE

Great show... ice cracking... this came out on You Tube some days ago...

[Andreas Muenchow]

Werther:

Whow ... and thank you so much for sharing, I'll use this in my future classes as this is oceanography 101 in dramatic action ... and, please, someone tell Neven quickly, if he does not make a blog post on this, I will. This video has all the drama and immediate human impact with very simple physics that the Petermann calvings do not.

It is a dam-breaking problem that has analytical solutions that I blogged about in the link given, but it applies here as well. Physics is both grand and universal, that's why I love it.

[Neven]

Go ahead and use it, Andreas. I'll do a blog post on it tomorrow.

It scared me out of my wits. Just imagine being there. There are similar videos, BTW. I saw one a couple of months back with a boat full of tourists where they are first bombarded with small pieces of ice, and then cometh the tsunami. Brrrr....

[Andreas Muenchow]

Petermann does NOT work that way, I described the Petermann calving to some media folks as a gentle and very quiet affair similar to a rubber duckie pushed out to sea from the deck of a flat pool.

I wait until your post, Neven, then I can either reference back and find an angle that you did not cover. Humbold Glacier, the next glacier south from Petermann may calve this way, perhaps, as it does not have a floating ice shelf, I think.

[Tzupancic1]

This is a bit off topic but related to Greenland. I have been following the large section of fast ice along the northeast coast of Greenland in the "North East Water" region. Checking the Modis images today I see that two large sections have just broken off as well as a third large section more to the south. The ice along the northeastern edge had begun to erode to a lesser extent on day 200.

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r02c03.2012203.terra.1km

[Twemoran]

I experienced that form of calving at Glacier Bay in Alaska many decades ago - from a much larger vessel. From the photos I've seen of Kane Basin with the cliff like face of Humboldt looming above, I've assumed similar effects would occur when the face is undercut.

BTW - Pii2012 seems to be making good time heading out, possibly getting an assist from the tributary glaciers adding rubble into the gap.

Terry

[Neven]

Tzupancic, I did an animation two years ago when a piece of ice the size of Corsica broke off in the same region. At least a week earlier than this year.

[Tzupancic1]

Thanks Neven,

As I recall, last year there was less going on here. I was curious how stable this ice has been, and in particular, if the entire thing ever breaks up. I suspect that this year's breakup of this fast ice is just getting started.

[Tzupancic1]

Looking further into the stability of the North East Water fast ice, I looked back at the Science paper from last August by Funder et al., 2010. "A 10,000-Year Record of Arctic Ocean Sea-Ice Variability—View
from the Beach." http://www.sciencemag.org/content/333/6043/747.abstract

In Figure 1C they include a graphic of this region that shows the fast ice in place at the 2007 minimum. However, in the figure legend they write "In late September,
the land-fast ice was swept away, and until late November, the north coast was exposed to dense pack ice—a situation that has characterized the past decade (26)". 26 is Greenland Ice Chart 1999–2009 (Danish Meteorological Institute, Copenhagen, Denmark); available www.dmi.dk/dmi/index/gronland/iskort.htm.

That's as far as I have gotten, but the implication is that this fast ice has routinely broken free. Still I'm curious about the details.

[Twemoran]

Tzupancic

"In the summer of 2001 the dramatic northerly retreat of sea ice in the East Greenland Current (EGC) united with the polynya to form what one could describe as an almost open continental shelf sea."

From
http://www.issibern.ch/teams/Polynya/

Terry

[Tzupancic1]

Twemoran,

Thanks for the great link. Most interesting to read,
"In the summer of 2001 the dramatic northerly retreat of sea ice in the East Greenland Current (EGC) united with the polynya to form what one could describe as an almost open continental shelf sea. This scenario, possibly unprecedented in recorded history, continued for the next four years and led to the NEW being described as having morphed into the Marginal Ice Zone (MIZ) (Smith and Barber, 2007). In fact one could legitimately ask if there is still a NEW polynya or has it ceased to function as such?
However in the summer of 2005, which corresponded to a new minimum in the extent of sea ice in the Arctic, the NEW returned, albeit smaller than usual.
... etc

"unprecedented in recorded history" back in 2001.

[Climate Changes]

http://www.youtube.com/watch?feature=player_embedded&v=GoRtyAJdcK4

Lucky lot...

[Rob Dekker]

About the two idiots who got their boat way too close to a glacier calving front, I recall this post by William Connolley, on a similar video from Antarctica :
http://scienceblogs.com/stoat/2012/03/21/collapsing-iceberg/

William's notes kind of sum up my thoughts in this kind of videos :

The change from "Oh look that’s fun, lets stop and watch" to the brief "Oh shit" to the "Ha ha, we all lived, that was great fun" to "who got it on video?" is oh-so-typical of our species.

[Espen Olsen]

Andreas,

"I described the Petermann calving to some media folks as a gentle and very quiet affair similar to a rubber duckie pushed out to sea from the deck of a flat pool."

I don't agree with you it is a "quiet affair", when ice break you can definitely hear it, and the sound is not comparable with anything else, but I agree, it was/is not the tsunami kind of break of you see elsewhere like at Humboldt, and it well illustrated with the Modis images, the ice in front of the calved ice did not move a lot.

[Neven]

Lodger, researchers from the Alfred Wegener Institute are going to measure the amount of methane in waters around Svalbard, and will be using one of those AUVs (Autonomous Underwater Vehicle) you mentioned earlier:

Unfortunately it isn't pink... ;-)

Press release here (in German).

[Wayne Kernochan]

@Neven: it appears to be a Yellow Submarine -- in which, according to 1970s researchers Lennon & McCartney, we all live. It is therefore a perfectly appropriate vehicle for assessing the methane we are emitting :) - w

[Artful Dodger]

Yellow... "it's the new pink!"

[Andreas Muenchow]

Oh boys, The Daily Mail turned Werther's YouTube link into a story:

http://www.dailymail.co.uk/news/article-2177617/Glacier-watchers-bargain-falling-wall-ice-creates-tsunami.html?ito=feeds-newsxml

but we all read it here first ;-)